Control for spill ports in free-piston units



May 10, 1949. R. s. BUCK ETAL 2,469,712

CONTROL FOR SPILL PORTS IN FREE-PISTON UNITS Filed Aug. 25; 1.944 2 Sheets-Sheet 1 FIG.

mvzmoas (DO N R. s. BUCK ETAL I CONTROL FOR SPILL PORTS IN FREE-PISTON UNITS Filed Aug. 23. 1944 May 10, 1949.

2 Sheets-Sheet 2 .M .m N..

Patented May 10, 1949 CONTROL FOB SPILL PORTS IN FREE-PISTON UNITS Richard 8. Buck, Glastonbury, and Walter A. Let!- with, Hartford, Coma, alslgnorl to United Aircraft Corporation, East poration of Delaware Hartford, Conn a cor- Application August 23, 1944, Serial No. 550,874

12 Claims.

relates to a control for the free-piston engine-and-com- Serial No. 550,884, flied August 23, 1944, on

which was issued Patent No. 2,441,272 of May.

11, 1948, discloses a band extending around the compressor cylinder and movable circumferentially to open or close the spill ports in the compressor cylinder by which to adjust the ef- A feature of opening fective' volume of the compressor. this invention is a device for closing or the ports by radial movement.

Another feature is a band extending around the compressor cylinder and adapted to be moved radially away from the ports by tangential movement of one of its ends.

A feature of the invention is a device which can be moved quickly with a small expenditure of energy into open or closed position with respect to the ports.

Other objects and advantages will be appar-- ent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

Fig. 1 is a sectional view piston unit.

Fig. 2 is a sectional view on line 2-2 of Fig. 1.

Fig. 3 is a fragmentary sectional view on line 3-3 of Fig. 2.

The unit shown includes an engine cylinder "I having reciprocating pistons l2 and It to which compressor pistons l6 and 18 in cylinders 20 and 22 are integrally connected. Sleeves 24 and 26 attached to the compressor pistons complete the reciprocating piston assemblies. The sleeves in combination with stationary pistons 28 and 30 form air spring cylinders.

The piston assemblies are moved apart by the burning of fuel injected into .engine cylinder l through one or more nozzles '32. Air compressed in the air spring cylinders on the power stroke returns the piston assemblies. The assemblies are always maintained at equal distances from the center of the engine cylinder by a linkage, not shown.

Intake manifold 42, which extends around the compressor and engine cylinders conducts air to intake valves 44 in the heads of the compressor cylinders, through which air alternately enters opposite ends of the cylinders. The compressed air leaves charge valves 46,

through the freealso at .opposite ends of the compressor cylinders and passes into a central scavenge chamber 48 and end chambers 50 and 52. These chambers may be interconnected by a scavenge manifold, not shown.

Compressed gas from the scavenge chambers enters engine ports 54 and 56 which are uncovered by pistons 12 and it at the end of the the cylinders through dis power stroke, thereby permitting air to be blown through the engine cylinder. Gas and air in the engine cylinders is discharged through exhaust ports It into exhaust manifold 60.

Each compressor cylinder has a number of axially-spaced. rows of spill ports 62 to permit discharge of air without compression from the cylinder. Each row of ports may be individually controlled by a band 64, Fig. 2, extending around the cylinder between projecting ribs 66 extending from the cylinder. One end of each band 64 is fixed as by a rivet 68 to a lug 89 on surrounding maniiold 42, and the other end of the band is connected to the projecting rod 10 of a piston 12 moving in a cylinder 14, which may form a part of manifold 42.

Fluid under pressure admitted to the outer end of cylinder ll will cause radially against the cylinder for closing the spill ports. A coil spring 16 between the ends of the spring may move the ends of the band apart for'opening the ports by moving the band radially away from the cylinder. The intake manifold 42 which forms a casing around the compressing cylinder limits. the outward movement of the band and assures a separation of the band from the cylinder throughout its length. Each row of ports 62 has a separate band so that each row is individually closed or opened. Guides I! extending in from the manifold 42 at opposite sides of each band guide the band during its opening or closing.

Fluid may be admitted to the cylinder 12 for closing the band by a servo-motor which is in turn actuated by a master control of the type shown in the copending application of Kalitinsky, Serial No. 550,886, filed August 23, 1944, on which Patent No. 2,441,273 has been issued, May 11, 1948.- Such an arrangement is claimed in said copending application and, not being a part of this invention, will not be described in detail.

The use of spill ports in controlling the stroke of a free-piston unit is claimed in the copending Cooper application, Serial No. 531,301, filed April 15, 1944, on which Patent No. 2,458,147 of January 4, 1949, has been issued.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departing from its spirit as defined by the following claims.

We claim: I

l. A free-piston unit including an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a unit, said compressor cylinder having at least one row of circumferentially arranged ports, and a band extending circumferentially around said compressor cylinder and overlying the ports, and

the band to be moved means for moving said band radially to close or open the ports.

2. A free-piston unit includingan engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a unit, said compressor cylinder having at least one row of circumferentially arranged ports and a band L extending eircumferentially around said compressor cylinder and overlying the ports, said band being movable radially away from the cylinder by substantially tangential movement of at least one end of the band and means for moving said one end of the band substantially tangentially.

3. A free-piston unit including an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a unit, said compressor cylinder @having at least one row of circumferentially arranged ports and a band extending around said compressor cylinder and overlying the ports, and means for moving said band radially away from the cylinder by endwise movement of at least one end of the band, and a casing around and spaced from said compressor cylinder and against which the band is moved.

4. A free-piston unit including an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a. unit, said compressor cylinder having at least one row of circumferentially extending ports, and a band extending around said compressor cylinder and overlying the ports, and means for moving said band radially to close or open the ports, one end of said band being fixed, and means for moving the other end of the band tangentially to cause the band to move radially away from the compressor cylinder.

5. A free-piston unit including an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a unit, said compressor cylinder having at least one row of circumferentially extending ports, and a band extending around said compressor cylinder and overlying the ports, and means for moving said band radially to close or open the ports, one end of said band being fixed, means for moving the other end of the band tangentially to move the band away from the cylinder, and a casing around said compressor cylinder against which the band is moved.

6. A free-piston engine-and-compressor unit having an engine cylinder and piston, a compressor cylinder and piston, the compressor piston moving with the engine piston, said compressor cylinder having a number of axially spaced rows of ports, and a band for each row of ports extending around the compressor cylinder and overlying and closing the associated row of ports, at least one of said bands being movable radially away from and toward the cylinder to open or close the ports.

7. A free-piston engine-and-compressor unit having an engine cylinder and piston, a compressor cylinder and piston, the compressor piston moving with the engine piston, said compressor cylinder havin a number of axially spaced rows of ports, and a number of .closure elements, one for each row of ports, arranged around the compressor cylinder, each element being independently movable radially of the cylinder to open or close the ports.

8."A free-piston engine-and-compressor unit having an engine cylinder and piston, a compressor cylinder and piston, the compressor piston moving with the engine piston, said compressor cylinder having a number of axially spaced rows of ports, a number of bands, one for each row of ports, extending around the compressor cylinder and overlying and closing the associated row of ports, each band being separately movable radially of the cylinder to open or close the ports associated therewith, and a casing around the compressor cylinder against which the bands are moved in opening the ports.

9. A compressor cylinder and piston, said cylinder having at least one row of circumferentially arranged ports, and a band extending around said cylinder and overlying and closing the ports and means for moving said band radially of the cylinder to close or open the ports.

10. A compressor cylinder and piston, said cylinder having at least one row of circumferentially arranged ports and a band extending around said cylinder and overlying and closing the ports, said band being movable radially away from the cyl-' inder by tangential movement of at least one end of the band, and a casing around said cylinder against which the band is moved.

11. A free-piston unit including an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a unit, said compressor cylinder having at least one row of circumferentially arranged ports and a band extending around said compressor cylinder and overlying and closing the ports, said band being movable radially away from the cylinder by substantially tangential movement of at least one end of the band, a casing around said cylinder against which the band is moved, and guides for the band.

12. A free-piston unitincluding an engine cylinder and piston, a compressor cylinder and piston, said pistons being interconnected to move as a unit, said compressor cylinder having at least one row of circumferentially arranged ports and a band extending around said compressor cylinder and overlying and closing the ports, said band being movable radially away from the cylinder by endwise movement of at least one end of the band, a casing around said cylinder against which the band is moved, and guides engaging opposite sides of the band.

, RICHARD S. BUCK.

WALTER A. LEDWITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

